Add TempFile and TempDirectory utilities

[Copilot]

Adds TempFile and TempDirectory — IDisposable wrappers that create uniquely-named resources under the system temp path and delete them on disposal.

• PowerKit/TempFile.cs — partial class; Create() generates a GUID-based .tmp path under Path.GetTempPath() and creates the file via File.Create; Dispose() deletes it (idempotent — File.Delete does not throw when the file is absent)
• PowerKit/TempDirectory.cs — same pattern; Create() generates and materializes a unique subdirectory; Dispose() recursively deletes it, suppressing DirectoryNotFoundException

using var file = TempFile.Create();
File.WriteAllText(file.Path, "hello");

using var dir = TempDirectory.Create();
File.Copy(file.Path, Path.Combine(dir.Path, "copy.txt"));
// Both cleaned up automatically on disposal

Modeled after the CliWrap test utilities of the same name, adapted for general-purpose library use.

[Copilot]

Pull request overview

Adds disposable helpers for managing temp-file and temp-directory lifetimes in PowerKit, with accompanying tests to validate basic creation/cleanup behavior.

Changes:

• Introduces TempFile and TempDirectory disposable wrappers under PowerKit/.
• Adds xUnit test coverage for temp file/directory creation and disposal.
• Implements directory materialization on create and recursive cleanup on dispose.

Reviewed changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated 6 comments.

File	Description
PowerKit/TempFile.cs	Adds TempFile wrapper + factory method for generating a temp .tmp path and deleting it on dispose.
PowerKit/TempDirectory.cs	Adds TempDirectory wrapper + factory method that creates a unique temp directory and deletes it on dispose.
PowerKit.Tests/TempFileTests.cs	Adds tests for TempFile create/dispose behavior.
PowerKit.Tests/TempDirectoryTests.cs	Adds tests for TempDirectory create/dispose behavior.

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[Tyrrrz]

@copilot if there are of our own tests that could benefit from TempFile/TempDirectory, apply the necessary changes

[Copilot]

@copilot if there are of our own tests that could benefit from TempFile/TempDirectory, apply the necessary changes

After reviewing all existing test files, none of them create or manage real temp files/directories on disk — they all use in-memory alternatives (MemoryStream, StringReader, etc.). There are no existing tests that would benefit from TempFile/TempDirectory.

[Tyrrrz]

@copilot please fix failing test

[Copilot]

@copilot please fix failing test

Fixed in a9c01eb. The simplification of Create() introduced a compile error: without the FQNs, Path inside the partial class resolves to the instance property TempFile.Path rather than System.IO.Path. Restored System.IO.Path.* FQNs in the static method — this is the correct approach since there's a genuine naming collision.